Global regulation in Erwinia species by Erwinia carotovora rsmA, a homologue of Escherichia coli csrA: repression of secondary metabolites, pathogenicity and hypersensitive reaction

Mukherjee, Asita; Cui, Yaya; Liu, Yang; Dumenyo, C. Korsi; Chatterjee, Arun

doi:10.1099/13500872-142-2-427

Cited by 90 publications

(78 citation statements)

References 54 publications

(95 reference statements)

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“…However, judging from the swimming and twitching abilities of an rsmA mutant, we believe that a major involvement of RsmA in the control of these processes is unlikely. By contrast, the RsmA homolog CsrA positively regulates the synthesis of flagella and swimming in E. coli (57), whereas in Erwinia spp., RsmA negatively affects motility (34).…”

Section: Discussionmentioning

confidence: 99%

Positive Control of Swarming, Rhamnolipid Synthesis, and Lipase Production by the Posttranscriptional RsmA/RsmZ System inPseudomonas aeruginosaPAO1

et al. 2004

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In Pseudomonas aeruginosa, the small RNA-binding, regulatory protein RsmA is a negative control element in the formation of several extracellular products (e.g., pyocyanin, hydrogen cyanide, PA-IL lectin) as well as in the production of N-acylhomoserine lactone quorum-sensing signal molecules. RsmA was found to control positively the ability to swarm and to produce extracellular rhamnolipids and lipase, i.e., functions contributing to niche colonization by P. aeruginosa. An rsmA null mutant was entirely devoid of swarming but produced detectable amounts of rhamnolipids, suggesting that factors in addition to rhamnolipids influence the swarming ability of P. aeruginosa. A small regulatory RNA, rsmZ, which antagonized the effects of RsmA, was identified in P. aeruginosa. Expression of the rsmZ gene was dependent on both the global regulator GacA and RsmA, increased with cell density, and was subject to negative autoregulation. Overexpression of rsmZ and a null mutation in rsmA resulted in quantitatively similar, negative or positive effects on target genes, in agreement with a model that postulates titration of RsmA protein by RsmZ RNA.Pseudomonas aeruginosa is a ubiquitous saprophyte and an opportunistic human pathogen which synthesizes numerous extracellular products including elastase, LasA protease, alkaline protease, phospholipase C, lipase, exotoxin A, rhamnolipids, hydrogen cyanide (HCN), and pyocyanin (25, 63). The production of these exoproducts, most of which can act as virulence factors, is positively controlled by two quorum-sensing signal molecules, N-(3-oxododecanoyl)-homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-homoserine lactone (C4-HSL), which activate the transcription factors LasR and RhlR, respectively (20,26,59). The las and rhl systems are organized in a hierarchical manner such that the las system exerts transcriptional control over both rhlR and rhlI (26). A third signal molecule, 2-heptyl-3-hydroxy-4(1H)-quinolone, the synthesis and activity of which is linked to the las and rhl circuitry, is also required for virulence factor production and, in particular, for rhl-dependent exoproducts including pyocyanin and PA-IL lectin (41).Motility helps P. aeruginosa to colonize niches (10); three types of motility are observed, i.e., swimming, twitching, and swarming (24, 44). Whereas swimming in liquid media depends on flagella, twitching on solid media requires type IV pili.Swarming on semisolid media results from a combination of both types of motility and also requires rhamnolipid production (24, 46). Rhamnolipids are biosurfactants which not only enhance bacterial surface translocation by virtue of their wetting properties but also stimulate solubilization and degradation of hydrocarbons (35) and act as heat-stable hemolysins (21).The production of N-acyl-homoserine lactones (AHLs) and the expression of many virulence determinants in P. aeruginosa is negatively controlled at a posttranscriptional level by the small RNA-binding protein RsmA (42,43). This regulator is a homolog of CsrA in E...

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Section: Discussionmentioning

confidence: 99%

Positive Control of Swarming, Rhamnolipid Synthesis, and Lipase Production by the Posttranscriptional RsmA/RsmZ System inPseudomonas aeruginosaPAO1

et al. 2004

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“…The RsmA mutants overproduced pectinases, cellulases, proteases, and the HrpN (harpin) protein, while exoenzyme synthesis was inhibited by multicopy rsmA expressed in trans (94). Furthermore, rsmA can downregulate a physiologically diverse spectrum of phenotypes, including flagellum synthesis, antibiotic production, pigment synthesis, and EPS production in various Erwinia species (338).…”

Section: Role Of Gacs-gaca In Regulation Of Plant-associated Phenotypesmentioning

confidence: 99%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

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Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described

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“…It is now apparent that Rsm and Rsm-like systems control diverse phenotypes in many prokaryotic species. In Erwinia, this regulatory system plays a critical role by affecting plant interaction, extracellular enzyme production, extracellular polysaccharide synthesis, swarming motility, secondary metabolite production, and the quorumsensing system (8,11,12,31,34,35). In Escherichia coli, a homologous system comprising CsrA (equivalent to RsmA) and csrB (equivalent to rsmB) RNA, controls glycogen synthesis, metabolism of acetate, motility and flagellum biosynthesis, and biofilm formation (21,27,40).…”

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confidence: 99%

RsmA and the Quorum-Sensing Signal,N-[3-Oxohexanoyl]-l-Homoserine Lactone, Control the Levels ofrsmBRNA inErwinia carotovorasubsp.carotovoraby Affecting Its Stability

2002

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RsmA (for regulator of secondary metabolism), RsmC, and rsmB RNA, the components of a posttranscriptional regulatory system, control extracellular protein production and pathogenicity in Erwinia carotovora subsp. carotovora. RsmA, an RNA binding protein, acts as a negative regulator by promoting message decay. rsmB RNA, on the other hand, acts as a positive regulator by neutralizing the effect of RsmA. RsmC modulates the levels of RsmA and rsmB RNA by positively regulating rsmA and negatively controlling rsmB. The level of rsmB RNA is substantially higher in RsmA ؉ bacteria than in RsmA ؊ mutants. We show that rsmB RNA is more stable in the presence of RsmA than in its absence. RsmA does not stimulate the expression of an rsmB-lacZ transcriptional fusion; in fact, the ␤-galactosidase level is somewhat higher in RsmA ؊ bacteria than in RsmA Rsm (for regulator of secondary metabolism) is a novel type of posttranscriptional regulatory system which has a profound effect on bacterial metabolism and behavior. Rsm of Erwinia carotovora subsp. carotovora consists of three major components: an RNA binding protein, RsmA, which promotes RNA decay (8, 11); an untranslated RNA molecule, rsmB, which neutralizes RsmA action, apparently by sequestering RsmA (29); and RsmC, which positively regulates rsmA and negatively controls rsmB RNA levels (13). It is now apparent that Rsm and Rsm-like systems control diverse phenotypes in many prokaryotic species. In Erwinia, this regulatory system plays a critical role by affecting plant interaction, extracellular enzyme production, extracellular polysaccharide synthesis, swarming motility, secondary metabolite production, and the quorumsensing system (8,11,12,31,34,35). In Escherichia coli, a homologous system comprising CsrA (equivalent to RsmA) and csrB (equivalent to rsmB) RNA, controls glycogen synthesis, metabolism of acetate, motility and flagellum biosynthesis, and biofilm formation (21,27,40). There are substantial data indicating the existence of the regulatory system in various enterobacterial species, including human pathogens (2,3,5,9,14,40). Moreover, recent studies of several Pseudomonas species have demonstrated that RsmA-rsmB regulatory systems control secondary metabolite production and plant interaction.For example, in Pseudomonas aeruginosa, overexpression of rsmA reduces the levels of protease (Prt), elastase, and staphylolytic (LasA Prt) activity, as well as those of the PA-IL lectin, hydrogen cyanide, and pyocyanin. In Pseudomonas fluorescens, overexpressed prrB, which is structurally similar to rsmB, increases the production of Phl (2,4-diacetylphloroglucinol) and hydrogen cyanide (1,6,7,38). In Pseudomonas syringae pv. tomato strain DC3000, RsmA reduces the production of extracellular proteins, causes attenuation of pathogenicity in Arabidopsis thaliana, and lowers the efficiency of the induction of the hypersensitive reaction in tobacco

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Global regulation in Erwinia species by Erwinia carotovora rsmA, a homologue of Escherichia coli csrA: repression of secondary metabolites, pathogenicity and hypersensitive reaction

Cited by 90 publications

References 54 publications

Positive Control of Swarming, Rhamnolipid Synthesis, and Lipase Production by the Posttranscriptional RsmA/RsmZ System inPseudomonas aeruginosaPAO1

Positive Control of Swarming, Rhamnolipid Synthesis, and Lipase Production by the Posttranscriptional RsmA/RsmZ System inPseudomonas aeruginosaPAO1

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

RsmA and the Quorum-Sensing Signal,N-[3-Oxohexanoyl]-l-Homoserine Lactone, Control the Levels ofrsmBRNA inErwinia carotovorasubsp.carotovoraby Affecting Its Stability

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